1. Field of the Invention
The present invention relates to a method and a system for searching for relationships between base sequences in genes. More particularly, the present invention relates to a method and a system for searching for the relationships between a sample base sequence and known base sequences based on restriction fragment length polymorphisms (RFLP).
2. Description of Related Art
An initial bacterial classification system has been constructed based on bacterial cell morphology, physiological properties, biochemical activities and the like. For the purpose of identifying an unknown bacterium based on this initial bacterial classification system, a plurality of physiological test results for a bacterium being identified are automatically recorded. The recorded physiological test results are compared with the physiological test results of known bacterial strains already recorded in a stored database. A search is made for the relationship between the unknown bacterium and known bacterial strains to infer the species name of the unknown bacterium. The identification method described above has been utilized in medical and clinical fields as well as in a wide variety of industrial fields such as cosmetics, food hygiene, quality control, and environmental hygiene.
However, precise definitions of species for eubacteria and archaeobacteria, which propagate by cell division, are difficult to construct, in contrast to eucaryotes, which reproduce sexually, and for which precise definitions have been established. Therefore, recently, a new classification system based on ribosomal RNA as a molecular clock has been constructed. To be more precise, in the new classification system, the bacteria are classified in accordance with differences in bacterial 16S rDNA sequences. As a result, there are large discrepancies between the results by the identification method described above and those according to 16S rDNA sequences.
To determine the base sequences, a method utilizing a sequencer device has been widely used. However, the sequencer device is expensive and the number of bases that one sequencer device can read is limited. Thus, the method utilizing a sequencer device is not efficient and incurs high costs for determining the base sequences.
Alternatively, a method has been used which involves digesting an unknown DNA molecule by restriction enzymes and inferring the base sequence thereof based on the lengths of resulting fragments, so as to determine the base sequence. However, this method requires a great amount of time and labor to infer the base sequence by restriction pattern matching of the unknown DNA molecule and known DNA molecules. Thus, this method is also inefficient for identifying base sequences.